Numerous steps are involved in the fabrication of microelectronic structures. Within the manufacturing scheme of fabricating integrated circuits selective etching of different surfaces of the semiconductor is sometimes required. Historically, a number of vastly different types of etching processes, to selectively remove material, have been successfully utilized to varying degrees. Moreover, the selective etching of different layers, within the microelectronic structure, is considered a critical and crucial step in the integrated circuit fabrication process.
Increasingly, reactive ion etching (RIE) is the process of choice for pattern transfer during via, metal line and trench formation. For instance, complex semiconductor devices such as advanced DRAMS and microprocessors, which require multiple layers of interconnect wiring, utilize RIE to produce vias, metal lines and trench structures. Vias are used, through the interlayer dielectric, to provide contact between one level of silicon, silicide or metal wiring and the next level of wiring. Metal lines are conductive structures used as device interconnects. Trench structures are used in the formation of metal line structures. Vias, metal lines and trench structures typically expose metals and alloys such as Al, Al/Cu, Cu, Ti, TiN, Ta, TaN, W, TiW, silicon or a silicide such as a silicide of tungsten, titanium or cobalt. The RIE process typically leaves a residue (of a complex mixture) that may include re-sputtered oxide material as well as possibly organic materials from photoresist and antireflective coating materials used to lithographically define the vias, metal lines and or trench structures.
Post RIE or other etch processing, plasma photoresist residue cleaning is typically conducted by ashing the patterned photoresist with a plasma containing a reactive agent typically activated reactive gas(es) such as, without limitation, an oxygen-containing gas for oxidative processes or a hydrogen containing gas for reductive processes. Like the RIE process, plasma etch or plasma ash cleaning leaves a combination of residues including organic materials (e.g., residual photoresist, antireflective materials, and the like) and plasma etch related byproducts such as oxides or halides of titanium, copper, or related metals depending upon the plasma etch chemistry and substrate being treated.
It would therefore be desirable to provide a selective cleaning composition and process capable of removing residues such as, for example, residues resulting from selective etching using plasmas and/or RIE and oxidative ash or reductive ashing processes. Moreover, it would be desirable to provide a selective cleaning composition and process, capable of removing residues such as etching and ashing residue, that exhibits high selectivity for the residue as compared to metals, high dielectric constant (“high k”) materials (e.g., materials having a dielectric constant greater than 4.1), silicon, silicide and/or interlevel dielectric materials including low dielectric constant (“low k”) materials (e.g., materials having a dielectric constant less than 4.0 or less than 3.5 or less than 3.0) such as deposited oxides that might also be exposed to the cleaning composition. It would be desirable to provide a composition that is compatible with and can be used with such sensitive low k or porous low k films such as, but not limited to, hydrogen silsequioxane (HSQ), methylsilsequioxane (MSQ), FOx, BLACK DIAMOND™ films manufactured by Applied Materials, Inc., and TEOS (tetraethylorthosilicate). In addition to the above, it would be desirable for a composition that is aqueous-based so that the disposal thereof will not harm the environment.